Method for controlling charging of packet data service

ABSTRACT

A method for controlling the charging of packet data service is disclosed, which includes: monitoring a number of event triggers; and when one of the event triggers is met, a Traffic Plane Function (TPF) requesting charging rules from a Charging Rule Function (CRF). In the preferred embodiments of the preferred embodiments of the present invention, the event triggers, which the TPF is required for request charging rules from the CRF according to are set by the CRF and then are provided to the TPF. Charging-relevant input information is provided in the request, based on which the CRF determines proper charging rules and sends the determined charging rules to the TPF. In this way, the timing that the TPF requests charging rules from the CRF becomes controllable, and redundant information caused by the unnecessary charging rule from the TPF becomes avoidable, which enables interaction between the TPF and the CRF more effective and the charging control of packet data service reasonable and perfect.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/502,921, filed on Mar. 28, 2005, which is a continuation ofInternational Application No. PCT/CN2005/000388, filed on Mar. 28, 2005.The International Application claims priority to Chinese PatentApplication No. 200410030955.8, filed on Apr. 1, 2004 and200410033721.9, filed on Apr. 9, 2004. The afore-mentioned patentapplications are hereby incorporated by reference in their entireties.

FIELD OF THE TECHNOLOGY

The present invention relates to a method of charging, and morespecifically to a method of charging control for packet data service.

BACKGROUND OF THE INVENTION

With the wide application of packet data service, how to charge packetdata service accurately and reasonably has become a common concern ofoperators.

FIG. 1 is a flowchart illustrating an activation, data transmission andde-activation of a Packet Data Protocol Context (PDP Context). As shownin FIG. 1, in General Packet Radio Service (GPRS), an implementingprocedure of PDP Context activation, data transmission and de-activationincludes the following steps:

Step 101: A User Equipment (UE) sends an Activate PDP Context Request toa Serving GPRS Support Node (SGSN), and this Activate PDP ContextRequest carries information of a Network Layer Service Access PointIdentifier (NSAPI), PDP type, an Access Point Name (APN), a plurality ofQuality of Service (QoS) parameters, a Transaction Identifier (TI) andso on, where NSAPI is used as a component of a Tunnel Identifier(TEID)between the SGSN and a Gateway GPRS Support Node (GGSN) toidentify the PDP Context. The PDP Type includes the Peer-Peer Protocol(PPP) type, Internet Protocol (IP) type, etc. The APN may be providedfor the SGSN by the UE, by which the SGSN addresses a corresponding GGSNand the GGSN determines the external network to be accessed by the UE,or the UE may choose not to provide the APN for the SGSN, in that case,the SGSN selects the default APN according to the subscriber informationof the UE. The QoS parameters represent the quality required by thepacket data service specified by the UE. The TI is used for the UE toidentify a PDP context.

Step 102: After receiving the Activate PDP Context Request, the SGSNperforms a security check and encryption with the UE, and this step isoptional.

Step 103: the SGSN analyses GGSN address information according to theAPN, if the SGSN finds the GGSN address information according to theAPN, the TEID is created for the PDP Context. The TEID may be acombination of an International Mobile Subscriber Identity (IMSI) andthe NSAPI to uniquely identify a PDP Context between SGSN and GGSN. Thenthe SGSN sends a Create PDP Context Request to the GGSN and the CreatePDP Context Request carries PDP type, PDP address, APN, QoS parameters,TEID, and a select mode. The PDP address is an IP address of the UE,which is an optional parameter. When a Create PDP Context Requestdoesn't carry a PDP address therein, the IP address may be allocated bythe GGSN in the subsequent process, or by a Packet Data Network (PDN)that is finally connected with the UE. The select mode refers to anAPN-selecting mode, namely whether the APN is selected by the UE or bythe SGSN. If the GGSN address information is not accessed for the SGSNaccording to the APN, the SGSN rejects the Activate PDP Context Requestfrom the UE.

Step 104: After receiving the Create PDP Context Request, the GGSNdetermines an external PDN according to the APN, then allocates aCharging ID, starts charging, and confers on QoS. The GGSN sends aCreate PDP Context Response back to the SGSN, when the service qualityrequirement is met. The Create PDP Context Response carries theinformation of TEID, PDP address, Backbone Bearer protocol, QoSparameters, and Charging ID. When the GGSN does not meet the servicequality requirement of the QoS parameters, the GGSN rejects the CreatePDP Context Request from the SGSN, and then the SGSN rejects theActivate PDP Context Request from the UE.

Step 105: After receiving the Create PDP Context Response, the SGSN addsthe NSAPI and the GGSN address information into the PDP Context in orderto identify this PDP Context, selects wireless precedence according toQoS parameters, and then returns an Activate PDP Context Accept to theUE. The Activate PDP Context Accept carries the information of PDP type,PDP address, TI, QoS parameters, wireless precedence, and a number ofPDP configuration options. Moreover, the SGSN starts charging. The UEreceives the Activate PDP Context Accept and establishes a route withthe GGSN. By this time the transmission channel between the UE and thePDN is established and data transmission is able to start.

Step 106: The UE transmits data with the PDN through the SGSN and theGGSN.

Step 107: On finishing the data transmission, the UE sends a DeactivatePDP Context Request to the SGSN and the Deactivate PDP Context Requestcarries the TI.

Step 108: After receiving the Deactivate PDP Context Request, the SGSNperforms security checks and encryption with the UE, and this step isoptional.

Step 109-Step 111: The SGSN sends a Delete PDP Context Request carryingthe TEID to the GGSN. After receiving the Delete PDP Context Request,the GGSN ends the charging of the UE, deletes the PDP Contextcorresponding to the TEID, and then sends a to the SGSN. The Delete PDPContext Response carries the TEID. After receiving the Delete PDPContext Response, the SGSN ends the charging of the UE, deletes the PDPContext corresponding to the TEID, and then sends a Deactivate PDPContext Response carrying the TI to UE. After receiving the DeactivatePDP Context Response, the UE deletes the PDP Context corresponding toTI.

As shown in FIG. 1, in the present GRPS charging system, the chargingstarts when the PDP context is activated and comes to its end when thePDP context is de-activated, which means the present charging system canonly charges according to a transmitted data flow or an activate timeduration of the PDP context. In practice, however, after establishing atransmission channel with the PDN, the UE performs a plurality ofservices based on one activated PDP Context, i.e. if the PDN is able toprovide a plurality of services, such as Send/Receive Email service,Wireless Application Protocol (WAP) based browse service, File TransferProtocol (FTP) based file transfer service and so on, an activated PDPContext is able to bear various services provided by the PDN after theUE establishes a transmission channel with this PDN. Meanwhile operatorsor service providers may adopt different charging approaches fordifferent charging modes of various services, for instance, Send/ReceiveEmail service may be charged based on trigger times of Sending andReceiving events, WAP browse service may be charged according to flow,file transfer service may also be charged according to flow, and yet, acharging rate of WAP browse service is different from that of filetransfer service. Thus, it is totally impossible to perform separatecharging with the existing GPRS charging system for different servicesthe same PDP Context bears.

In view of the above, it is being discussed in the 3rd GenerationPartnership Project (3GPP) as to how to implement IP Flow Based Charging(FBC). As far as a packet data service is concerned, all the transmittedand received IP Flows or IP Packets when a LE user uses the service maybe called Service Data Flow, i.e. the Service Data Flow is a set of aplurality of IP Flows, therefore the IP Flow Based Charging can trulyreflect the resource occupation of a certain service. The IP Flow BasedCharging can be described like this: IP Flows of different services thatthe same PDP Context bears are separately screened out through somefilters similar to sieves, then the IP Flows that are screened out bydifferent filters are separately charged so as to reach the object ofseparately charging different Service Data Flows. In this way, acharging granularity based on IP Flows is far less than that based on aPDP Context. The charging granularity may be regard as the size of ahole of a sieve, therefore the charging granularity based on one PDPContext will be like a sieve hole determined by one PDP Context whilethe charging granularity based on IP Flow will be like a sieve holedetermined by one IP Flow, that is, there will be more than one sieveholes contained in one PDP Context. Therefore, comparing with thecharging based on one PDP Context, charging based on IP Flow can providemore charging approaches for operators or service providers.

In 3GPP, aspects of FBC like system architectures, function requirementand flow of interactive messages are described. The FBC systemarchitecture supporting online charging is shown in FIG. 2A, in whichOnline Charging System (OCS) 206 is composed of Service Control Point(SCP) 201 of Customized Application for Mobile Network Enhanced Logic(CAMEL) and a service data flow based Credit Control

Function (CCF) 202. CCF 202 is connected with service data flow basedCharging Rule Function (CRF) 203 through an interface Ry. The CRF 203 isconnected with an Application Function (AF) 204 through an interface Rxand with the Traffic Plane Function (TPF) 205 through an interface Gx.The CCF 202 is connected with TPF 205 through an interface Gy.

The FBC system architecture supporting offline charging is shown in FIG.2B, in which the CRF 203 is connected with the AF 204 through aninterface Rx and with the TPF 205 through an interface Gx, and the TPF205 is connected with a Charging Gateway Function (CGF) 207 and aCharging Collection Function (CCF) 208 respectively through Gz.

According to the 3GPP provision for functions implementing the FBC, theTPF 205 bears IP Flows. During and the establishment of the IP Flowbearer, the TPF 205 sends a Charging Rule Request to the CRF 203 throughthe Gx interface. The Charging Rule Request carries relevant informationof subscriber and the UE, bearer characteristics, network information,and so on. The relevant information of subscriber and the UE may be aMobile Station ISDN (MSISDN), an International Mobile SubscriberIdentity (IMSI) and etc. In addition, the bearer may be modified duringthe IP Flow transmission. For example, when QoS parameters of the sameservice are different, charging rules may be different accordingly. Forinstance, the charging rate may be decrease as QoS parameters decrease.Therefore it is necessary to re-confer on QoS parameters. In this case,during the modification of the bearer, the TPF 205 resends a ChargingRule Request to the CRF 203 to request for new charging rules. The CRF203 selects a proper charging rule according to the said inputinformation provided by the TPF 205 and then returns the selectedcharging rule to the TPF 205. The charging rule includes information ofcharging mechanism, charging type, charging key, Service Data FlowFilter, and charging rule precedence. The charging mechanism may beonline charging or offline charging. The charging type may be a type oftime span based. The charging key is a parameter related with thecharging rate, and the CRF 203 may provide only parameters related withthe charging rate for the TPF 205, rather than directly provide thecharging rate for the TPF 205. The Service Data Flow Filter is used toindicate the TPF 205 which IP Flows are to be filtered, and then the TPF205 charges these filtered IP Flows according to the charging rules.Service Data Flow Filter may include IP quintuple having suchinformation as

Source/Destination IP Address, Source/Destination Port Number, andProtocol ID. For instance, the CRF 203 indicates the TPF 205 to filterthe IP Flow with the Source IP Address 10.0.0.1, Destination IP Address10.0.0.2, Source/Destination Port Number 20 and the protocol typeTransmission Control Protocol (TCP), and then charges the filtered IPFlow according to the charging rule. Finally, during the deletion of thebearer, the TPF 205 may as well send a Charging Rule Request to the CRF203 to request a new charging rule from the CRF. At this time, the CRF203 may request the TPF 205 to delete the previously installed chargingrule.

In addition, the CRF 203 may determine the charging rule according tothe input information of the AF 204 or OCS 20 apart from the inputinformation of the TPF 205. For example, the AF 204 may notify the CRF203 of the current service type used by the user, and the CRF 203 mayselect the corresponding charging rule according to this service type.

For a GPRS network, the TPF 205 is the GGSN, the AF is a service gatewayor a service server in the PDN and the CRF 203 is an added logicalentity. The TPF 205 is the executing point of charging rules and the CRF203 is the control point of charging rules.

FIG. 3A is the flow chart of issuing the charging rule when a bearer isestablished. As shown in FIG. 3A, the implementing procedure of issuingthe charging rule when a bearer is established includes the followingsteps:

Step 301A: The UE sends an Establish Bearer Service Request to the TPFwhile in a GPRS network the corresponding process is that the GGSNreceives a Create PDP Context Request.

Step 302A: After receiving the Establish Bearer Service Request, the TPFsends a Charging Rule Request to the CRF, and the Charging Rule Requestcarries the input information for the CRF to determine the chargingrule.

Steps 303A-304A: After receiving the Charging Rule Request, the CRFselects a charging rule according to the input information carried bythe Charging Rule Request, and then returns Provision Charging Rules.The Provision Charging Rules may carry the selected charging rule.

Steps 305A-306A: After receiving Provision Charging Rules, the TPFinstalls a new charging rule according to the charging rule selected bythe CRF, or deletes the original charging rule, or installs a newcharging rule while deleting the original one.

Then the TPF receives the Establish Bearer Service Request initiated bythe UE, returns an Establish Bearer Service Accept to the UE, andcontinues with the subsequent steps of the Establish Bearer process.

FIG. 3B is the flow chart of issuing the charging rule when a bearer ismodified. As shown in FIG. 3B, the implementing procedure of issuing thecharging rule when a bearer is modified includes the following steps:

Step 301B: The UE sends a Modify Bearer Service Request to the TPF whilein a GPRS network the corresponding process is that the GGSN receives anUpdate PDP Context Request.

Step 302B: After receiving the Modify Bearer Service Request, the TPFsends a

Charging Rule Request to the CRF, and the Charging Rule Request carriesthe input information for the CRF to determine the charging rule.

Steps 303B-304B: After receiving the Charging Rule Request, the CRFselects a charging rule according to the input information carried bythis Charging Rule Request, and then returns Provision Charging Rulescarrying the selected charging rule.

Steps 305B-306B: After receiving Provision Charging Rules, the TPFinstalls a new charging rule according to the charging rule selected bythe CRF, or deletes the original charging rule, or installs a newcharging rule while deleting the original one. Then the TPF receives theModify Bearer Service Request initiated by UE, returns a Modify BearerService Accept to the UE, and continues with the subsequent steps of theModify Bearer process.

FIG. 3C is the flow chart of issuing the charging rule when a bearer isdeleted. As shown in FIG. 3B, the implementing procedure of issuing thecharging rule when a bearer is deleted includes the following steps:

Step 301C: The UE sends a Remove Bearer Service Request to the TPF whilein a GPRS network the corresponding process is that the GGSN receives aDelete PDP Context Request.

Step 302C: After receiving the Remove Bearer Service Request, the TPFsends a Charging Rule Request to the CRF, and the Charging Rule Requestcarries the input information for the CRF to determine the chargingrule.

Steps 303C-304C: After receiving the Charging Rule Request, the CRFselects a charging rule according to the input information carried bythis Charging Rule Request, and then returns Provision Charging Rulescarrying the selected charging rule.

Steps 305C-306C: After receiving Provision Charging Rules, the TPFinstalls a new charging rule according to the charging rule selected bythe CRF, or deletes the original charging rule, or installs a newcharging rule while deleting the original one.

Then the TPF returns a Remove Bearer Service Accept to the UE, acceptsthe Remove Bearer Service Request initiated by the UE and continues withthe subsequent steps of the Remove Bearer process.

Besides, the CRF may also voluntarily send a charging rule to the TPF.For instance, in the data transmission process between the UE and theAF, after receiving the input information relating to charging of theAF, the CRF selects a proper charging rule according to the inputinformation provided by the AF, and then voluntarily issues the selectedcharging rule to the TPF. The specific implementing procedure of the AFproviding the input information of charging for the CRF is shown in FIG.4:

Step 401: The AF sends Application/Service Data Flow ChargingInformation to the CRF.

Step 402: After receiving the Application/Service Data Flow ChargingInformation, the CRF returns an Acknowledgement (Ack) to the AF tonotify the AF of already receiving the Application/Service Data FlowCharging Information sent by the AF.

FIG. 5 is the flow chart of the CRF voluntarily issuing the chargingrule to the TPF. As shown in FIG. 5, the implementing procedure of theCRF voluntarily issuing the charging rule to the TPF includes thefollowing steps:

Step 501: The CRF receives a certain Internal or External Trigger Eventand relevant information about this event, such as the event of the AFsending the input information of charging rule selection to the CRF.

Step 502: The CRF selects the corresponding charging rule according tothe acquired information. The acquired information may be thecharging-relevant input information provided by the AF. For instance,the user is using a certain service of AF, and the service has specialcharging requirement, e.g., the charging rate is different from that ofother services, therefore, the AF provides relevant charging informationof this service for the CRF. The acquired information may also be thecharging-relevant input information provided by TPF.

Step 503: The CRF sends the Provision Charging Rules to the TPF whenneeded, and the Provision Charging Rules may carry the selected chargingrule.

Step 504: After receiving Provision Charging Rules, the TPF installs anew charging rule according to the charging rule selected by the CRF, ordeletes the original charging rule, or installs a new charging rulewhile deleting the original one.

At present, the interactive mode concerning charging rule between theTPF and the CRF is defined in 3GPP Specification like this: The TPFsends a Charging Rule

Request to the CRF when a certain trigger event is met. The triggerevent may be an event of establishing, modifying or deleting the bearer.The CRF selects a proper charging rule according to the informationcarried in the Charging Rule Request and sends the selected chargingrule to the TPF. In this way, the event trigger of the Charging RuleRequest is controlled by the TPF. The event trigger of the Charging RuleRequest shall be set in the TPF in advance. Whenever the event ofestablishing, modifying or deleting the bearer is met, the TPF sends theCharging Rule Request to the CRF. However, for some cases, the QoSparameters modified have little differences compared with original QoSparameters when the QoS parameters are modified during the modificationof the bearer, and it is not necessary to modify the charging rules. Inthese cases, the CRF may select a charging rule similar to an originalone to send to the TPF when the TPF sends the Charging Rule Request,thereby creating a great of redundant information.

SUMMARY OF THE INVENTION

In view of the above, a method for charging control of packet dataservice is provided so as to make charging control of packet dataservice reasonable and perfect.

The method includes the steps of:

monitoring, by a Traffic Plane Function (TPF), an event trigger providedby a Charging Rule Function (CRF); and

sending, by the TPF, a charging rule request to the CRF, if the eventtrigger is met.

Preferably, event triggers each representing a bearer servicemodification are set by the CRF and then are provided to the TPF. Theevent triggers are set according to self-stored information in the CRF,or charging-relevant input information provided by an ApplicationFunction (AF), an Online Charging System (OCS), the TPF, or anycombinations of the AF, the OCS, and the TPF. The TPF stores the eventtriggers received from the CRF and monitors if any of the event triggersis met.

Preferably, the request sent from the TPF to the CRF when one of theevent triggers is met selectively includes an event identifier whichindicates a corresponding trigger event, and then the CRF responses forthe request by providing a charging rule in a charging rules provisionprocedure according to the trigger event.

In the preferred embodiments of the present invention, a plurality ofevent triggers is set such that the TPF requests corresponding chargingrules from the CRF when one of the event triggers is met. This eventtrigger may be set in the TPF or be determined by the CRF. The CRFdetermines the event triggers according which the TPF needs to requestcharging rules therefrom and then sends the event triggers to the TPF.When one of the event triggers is met, the TPF requests the chargingrules from the CRF and provides the charging-relevant input informationto the CRF. Then the CRF selects a proper charging rule according to thecharging-relevant input information and sends the selected chargingrules to the TPF. In this way, it is possible to control the timing ofthe TPF requesting charging rules from the CRF, avoiding redundantinformation caused by the TPF when sending unwanted Charging RuleRequests to the CRF, thereby making the information interaction betweenthe TPF and the CRF more effective and the charging control of packetdata service more reasonable and perfect. In the preferred embodimentsof the present invention, only static event triggers may be set in theTPF and the CRF does not need to provide any dynamic event trigger tothe TPF, thereby deduce the message load between the TPF and the CRF.

In addition, since it is possible for the CRF to obtaincharging-relevant input information provided by the AF or the OCS andthe charging-relevant input information may affect the charging rules.According to the method of the preferred embodiments of the presentinvention, the CRF is able to flexibly set event triggers according tothe charging-relevant input information and send the current eventtriggers to the TPF so that the TPF requests new charging rules from theCRF when a certain event trigger is met. In this way, flexible andvarious applications of charging rules may be implemented. However,functions mentioned above are completely impossible to be achieved bythe existing methods of interaction between the TPF and the CRF.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating a flow of PDP Context Activation,data transmission and De-activation;

FIG. 2A is a schematic diagram illustrating a structure of onlinecharging FBC system;

FIG. 2B is a schematic diagram illustrating a structure of offlinecharging FBC system;

FIG. 3A is a flowchart of issuing charging rules when bearer isestablished;

FIG. 3B is a flowchart of issuing charging rules when bearer ismodified;

FIG. 3C is a flowchart of issuing charging rules when bearer is deleted;

FIG. 4 is a flowchart of an AF providing charging input information fora CRF;

FIG. 5 is a flowchart of a CRF voluntarily issuing charging rules to aTPF;

FIG. 6 is a flowchart of a CRF controlling the sending of Charging RuleRequest by a TPF in this invention;

FIG. 7 is a schematic diagram illustrating Embodiment 1 of thisinvention; and

FIG. 8 is a schematic diagram illustrating Embodiment 2 of thisinvention.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiments of the present invention will be described indetail hereinafter with reference to the accompanying drawings.

In the preferred embodiments of the present invention, a plurality ofevent triggers is set such that a TPF requests corresponding chargingrules from a CRF when one of the event triggers is met. These eventtriggers may be set in the TPF or be determined by the CRF. The CRFdetermines the event triggers according which the TPF needs to requestthe charging rules therefrom, and then sends the event triggers to theTPF. When one of the event triggers is met, the TPF requests thecharging rule from the CRF and provides charging-relevant inputinformation. The CRF selects the proper charging rule according to thecharging-relevant input information and sends the selected charging ruleto the TPF. In this way, it is possible to control the timing of the TPFrequesting charging rules from the CRF, avoiding redundant informationcaused by the TPF when sending unwanted Charging Rule Requests to theCRF.

FIG. 6 is a flowchart showing the CRF controls the TPF to send theCharging Rule Requests. As shown in FIG. 6, the implementation of thecontrol includes the following steps:

Step 601: Setting a static event trigger enable the TPF to be triggeredto request a corresponding charging rule from the CRF in the TPF, suchas a static event trigger representing bearer establishment. When thestatic event trigger is met, the TPF sends the Charging Rule Request tothe CRF and the Charging Rule Request carries charging-relevant inputinformation, such as the information related with the subscriber and theUE, the bearer characteristics and the information related with thenetwork. This Charging Rule Request may also carry an event identifierto indicate that the current Charging Rule Request is triggered by thestatic event trigger.

In addition, more than one static event trigger may be set in the TPF,such as bearer establishment, bearer deletion and so on. When a certainstatic event trigger thereof is met, the TPF requests the charging rulefrom the CRF. On the other hand, the TPF may not set the static eventtrigger therein and periodically sends the Charging Rule Request to theCRF when the bearer is established.

Step 602: After receiving the Charging Rule Request, the CRF setsdynamic event triggers at which the TPF is required to request chargingrules, and then sends a Request Dynamic Event Report to the TPF. TheRequest Dynamic Event Report carries a list of dynamic event triggers,such as dynamic event trigger A, dynamic event trigger B and dynamicevent trigger C. These events may be a plurality of various ModifyBearer Events, such as the change of the SGSN, of the Public Land MobileNetwork (PLMN), of the Radio Access Technology (RAT) type, of theTraffic Flow Template, and of the QoS.

Step 603: According to the charging-relevant input information carriedby the Charging Rule Request, the CRF selects a proper charging rule,and then sends a Provision Charging Rule to the TPF. The ProvisionCharging Rule may carry the selected charging rule, such as chargingrule 1.

The information that the CRF sends to the TPF in steps 602 and 603 maybe carried in one message.

Step 604: After receiving the dynamic event trigger list and thecharging rule currently selected by the CRF, the TPF stores the dynamicevent trigger list, performs charging information statistics accordingto the selected charging rule, and monitors if any of the dynamic eventtrigger is met.

Step 605: The TPF monitors the occurrence of a dynamic event trigger A,and then sends a Charging Rule Request to the CRF. The Charging RuleRequest carries the occurrence indicator of the dynamic event trigger A.

Step 606: After receiving the Charging Rule Request, the CRF confirmsthat this Charging Rule Request is triggered by the dynamic eventtrigger A according to the occurrence indicator of the dynamic eventtrigger A and selects a proper charging rule also according to thedynamic event trigger A, and then sends the Provision Charging Rule tothe TPF. The Provision Charging Rule carries a newly-selected chargingrule, such as charging rule 2.

Step 607: After receiving the Provision Charging Rule, the TPF performscharging information statistics according to the Provision ChargingRule.

If there is more than one dynamic event trigger, the TPF continues tomonitor if any of other dynamic event triggers is met.

Step 608: the TPF monitors the occurrence of the dynamic event triggerB, and then sends the Charging Rule Request to the CRF. The ChargingRule Request carries the occurrence indicator of the dynamic eventtrigger B.

Step 609: After receiving the Charging Rule Request, the CRF confirmsthat this Charging Rule Request is triggered by the dynamic eventtrigger B according to the occurrence indicator of the dynamic eventtrigger B and selects a proper charging rule also according to thedynamic event trigger B, and then the CRF sends the Provision ChargingRule to the TPF. The Provision Charging Rule carries a newly-selectedcharging rule, such as charging rule 3.

Step 610: After receiving the Provision Charging Rule, the TPF takestatistics of the charging information according to the ProvisionCharging Rule.

The subsequent flow is similar to the above and no further descriptionis necessary.

Besides, during a same session, the same session means the same PDPContext in a GPRS network. The CRF may set in the same session dynamicevent triggers more than once and send these dynamic event triggers tothe TPF. For instance, when receiving charging-relevant inputinformation from the AF or the OCS, the CRF determines whether it isneeded to set a new dynamic event trigger according to thecharging-relevant input information, if yes, the CRF sets a new dynamicevent trigger and sends the point to the TPF. After receiving the newdynamic event trigger, the TPF stores the new dynamic event trigger andmonitors occurrence of the dynamic event trigger.

Moreover, since the static event triggers for requesting charging rulefrom the CRF may be set in the TPF, such routine events of bearer changeas bearer establishment, bearer modification, bearer deletion,occurrence of events when a fixed value of flow or time duration isreached and so on, may be reported to the CRF directly bypre-configuring static event triggers in TPF and there is no need forthe CRF to send dynamic event triggers to the TPF. For some operators orservice providers, there are usually some routine events of bearerchange; for example, it is always required for the TPF to report to theCRF when the service flow reaches 10M, or when the service has beenactivated for 100 minutes, without any other event point requiringdynamic configuration. In this case, only appropriate static eventtriggers are pre-configured in the TPF while no dynamic event triggerwill be issued by the CRF such that the signaling load between the TPFand the CRF can be reduced.

FIG. 7 is a schematic diagram illustrating Embodiment 1 of thisinvention, where the static event trigger for the TPF to request acharging rule from the CRF is set as bearer establishment, the CRF setthe dynamic event triggers at which the TPF is required to send theCharging Rule Request to the CRF when the bearer is modified or removed,and the implementing procedure showing the CRF controls the TPF to sendthe Charging Rule Request includes the following steps:

Step 701: The UE sends an Establish Bearer Service Request to the TPF.In a GPRS network the corresponding step is that the GGSN receivesCreate PDP Context Request.

Step 702: After receiving Establish Bearer Service Request, the TPFconfirms the occurrence of a static event trigger, and then sends theCharging Rule Request to the CRF. The Charging Rule Request carries thecharging-relevant input information, such as the relevant information ofa subscriber and the UE, bearer characteristics and network information.The request may also carry an event identifier for indicating that thecurrent Charging Rule Request is triggered by a static event trigger.

Steps 703-704: After receiving the Charging Rule Request, the CRFconfirms according to the event identifier that Charging Rule Request istriggered by a static event trigger, sets a dynamic event trigger listincluding bearer modification and bearer deletion, and then sends theRequest Dynamic Event Report to the TPF. The Request Dynamic EventReport carries the dynamic event trigger list. In addition, the CRF mayset a plurality of various values, such as various QoS parameterpriorities, in the dynamic event trigger of the bearer modification andeach value may be an independent dynamic event trigger.

Steps 705-706: The CRF selects a proper charging rule according to thecharging-relevant input information carried by the Charging RuleRequest, and then sends the Charging Rule Response to the TPF. TheCharging Rule Response carries the selected charging rule.

Steps 707-708: After receiving the dynamic event trigger list set by theCRF and the charging rule selected by the CRF, the TPF stores thedynamic event trigger list, performs charging information statisticsaccording to the charging rule, and monitors occurrence of the dynamicevent triggers. The TPF returns an Establish Bearer Service Acceptmessage to the UE, accepts an Establish Bearer Service Request initiatedby the UE and continues with the subsequent steps of the flow of thebearer establishment.

Step 709: After a while, the UE sends a Modify Bearer Service Request tothe TPF. In a GPRS network the corresponding step is that the GGSNreceives Update PDP Context Request.

Step 710: After receiving the Modify Bearer Service Request, the TPFconfirms that the dynamic event trigger of the bearer modification inthe dynamic event trigger list has occurred, and then sends the ChargingRule Request to the CRF. The Charging Rule Request carries theoccurrence indicator of the dynamic event trigger.

Steps 711-712: After receiving the Charging Rule Request, the CRFconfirms according to the occurrence indicator of dynamic event triggerthat the Charging Rule Request is triggered by the dynamic event triggerof bearer modification, selects a proper charging rule according to thebearer modification, and then sends the Provision Charging Rule to theTPF. The Provision Charging Rule may carry the selected charging rule.

Steps 713-714: After receiving the Provision Charging Rule, the TPFinstalls a new charging rule according to the charging rule selected bythe CRF, or removes the original charging rule, or installs a newcharging rule while deleting the original one, then returns the ModifyBearer Service Accept to the UE, accepts the Modify Bearer ServiceRequest initiated by the UE, and continues with the subsequent steps ofthe flow of the bearer modification.

Step 715: After a while, the UE sends a Remove Bearer Service Request tothe TPF. In a GPRS network the corresponding step is that the GGSNreceives Delete PDP Context Request.

Step 716: After receiving the Remove Bearer Service Request, the TPFconfirms that the dynamic event trigger of bearer deletion in thedynamic event trigger list has occurred, and then sends the ChargingRule Request to the CRF. The Charging Rule Request carries theoccurrence indicator of dynamic event trigger.

Steps 717-718: After receiving the Charging Rule Request, the CRFconfirms that the Charging Rule Request is triggered by the dynamicevent trigger of bearer deletion according to the occurrence indicatorof dynamic event trigger, selects the proper charging rule according tobearer deletion, and then sends the Provision Charging Rule to the TPF.The Provision Charging Rule may carry the selected charging rule.

Steps 719-720: After receiving the Provision Charging Rule, the CRFinstalls a new charging rule according to the charging rule selected bythe CRF, or deletes the original charging rule, or installs a newcharging rule while deleting the original one, and then returns theRemove Bearer Service Accept message to the UE, accepts the RemoveBearer Service Request initiated by the UE and continues with thesubsequent steps of the flow of the bearer deletion.

In the prior art, the AF sends the Application/Service Data FlowCharging Information to the CRF as the charging-relevant inputinformation for the CRF to the select charging rules. Then, in themethod provided in the preferred embodiments of the preferredembodiments of the present invention, the AF sends theApplication/Service Data Flow Charging Information to the CRF as theinput information for the CRF to dynamically set dynamic event triggers.

FIG. 8 is a schematic diagram illustrating Embodiment 2 of thisinvention, as shown in FIG. 8, the implementing procedure in the presentembodiment for the CRF to issue a dynamic event trigger to the TPFincludes the following steps:

Step 801: The CRF receives a certain Internal or External Trigger Event.For example, the AF provides an accredited activity for the users. Ifthe data flow of a certain service of this AF visited by one userreaches a set value, the subsequent charging rate of the user's to thisservice decreases. In this case, the AF requires the CRF to adopt afavorable charging rate to take charging information statistics forsubsequent data flow when the data flow of a certain service filterreaches a set value. Or, if the duration for which a user has accessed acertain service of this AF reaches a set value, the subsequent chargingrate of the user's to this service decreases. In this case, the AFrequires the CRF to adopt a favorable charging rate to perform charginginformation statistics for subsequent data flow when the duration forwhich a certain service filter has been used arrives at a set value.

Step 802: The CRF sets a dynamic event trigger, for instance, as whenthe data flow of a certain service filter reaches a set value or as whena certain service filter has been used for a set time span. Furthermore,the CRF may select a proper charging rule according to the informationcurrently acquired, such as the User/Terminal information, bearercharacteristics, and network information provided by the TPF.

Step 803: the CRF sends the Request Dynamic Event Report carrying thecurrent dynamic event trigger list to the TPF and requires the TPF torequest a charging rule from the CRF when a dynamic event triggerthereof is met.

Step 804: The CRF sends the Provision Charging Rule to the TPF and theProvision Charging Rule carries the charging rule currently selected.This step is optional.

Sep 805: The TPF receives the current dynamic event trigger list set bythe CRF and stores this dynamic event trigger list. If the TPF alsoreceives the Provision Charging Rule, the TPF installs a new chargingrule according to the charging rule selected by the CRF, or deletes theoriginal charging rule, or installs a new charging rule while deletingthe original one.

Step 806: After a while, the TPF monitors the occurrence of a dynamicevent trigger, and then sends the Charging Rule Request to the CRF. TheCharging Rule Request carries an occurrence indicator of dynamic eventtrigger.

Step 807-808: After receiving the Charging Rule Request, the CRFconfirms that which dynamic event trigger triggers this Charging RuleRequest according to the occurrence indicator of the dynamic eventtrigger. For example, the event may be an event that the data flow of acertain service filter reaches the set value or an event that a certainservice filter has been in use for a set time span. The CRF then selectsa proper charging rule according to this dynamic event trigger and sendthe Provision Charging Rule to the TPF. The Provision Charging Rule maycarry the selected charging rule.

Step 809: After receiving the Provision Charging Rule, the TPF installsa new charging rule according to the charging rule selected by the CRF,or deletes the original charging rule, or installs a new charging rulewhile deleting the original one.

In addition, the CRF may also dynamically set dynamic event triggersaccording to the charging-relevant input information sent by the OCSconcerning users' credit. The corresponding flow is basically the sameas the above and further description is not necessary.

In short, the above description is just a preferred embodiment of thisinvention and not to be construed as limits to the protection scopethereof.

1. A method for controlling charging of packet data service, comprising:monitoring, by a Traffic Plane Function (TPF), an event trigger providedby a Charging Rule Function (CRF); and sending, by the TPF, a chargingrule request to the CRF, if the event trigger is met.
 2. The methodaccording to claim 1, wherein the charging rule request carries theoccurrence indicator of the event trigger.
 3. The method according toclaim 1, wherein the charging rule request carries charging-relevantinput information which is provided to the CRF for charging ruleselection.
 4. The method according to claim 1, wherein the event triggerincludes a bearer modification event.
 5. The method according to claim4, wherein the bearer modification event comprises at least one of achange of a Serving GPRS Support Node (SGSN), a change of a Public LandMobile Network (PLMN), a change of a Radio Access Technology (RAT) type,a change of a Traffic Flow Template (TFT), and a change of Quality ofService (QoS).
 6. The method according to claim 1, further comprising:receiving, by the TPF, a charging rule from the CRF in a charging ruleprovision procedure.
 7. A communication system for controlling chargingof packet data service, wherein the communication system comprises aTraffic Plane Function (TPF) which is in communication with a ChargingRule Function (CRF), wherein the TPF is configured to monitor an eventtrigger provided by the CRF; and send a charging rule request to the CRFif the event trigger is met.
 8. The communication system according toclaim 7, wherein the charging rule request carries the occurrenceindicator of the event trigger.
 9. The communication system according toclaim 7, wherein the charging rule request carries charging-relevantinput information which is provided to the CRF for charging ruleselection.
 10. The communication system according to claim 7, whereinthe event trigger includes a bearer modification event.
 11. Thecommunication system according to claim 10, wherein the bearermodification event comprises at least one of a change of a Serving GPRSSupport Node (SGSN), a change of a Public Land Mobile Network (PLMN), achange of a Radio Access Technology (RAT) type, a change of a TrafficFlow Template (TFT), and a change of Quality of Service (QoS).
 12. Thecommunication system according to claim 9, the TPF is further configuredto receive a charging rule from the CRF in a charging rule provisionprocedure.
 13. A method for controlling the charging of packet dataservice, comprising: determining, by a Charging Rule Function (CRF), anevent trigger; providing, by the CRF, the event trigger to a TrafficPlane Function (TPF); and receiving, by the CRF, a charging rule requestfrom the TPF if the TPF monitors that the event trigger is met.
 14. Themethod according to claim 13, wherein the event trigger includes abearer modification event.
 15. The method according to claim 14, whereinthe bearer modification event comprises at least one of a change of aServing GPRS Support Node (SGSN), a change of a Public Land MobileNetwork (PLMN), a change of a Radio Access Technology (RAT) type, achange of a Traffic Flow Template (TFT), and a change of Quality ofService (QoS).
 16. The method according to claim 13, further comprising:sending, by the CRF, a charging rule to the TPF in a charging ruleprovision procedure.
 17. A communication system for controlling chargingof packet data service, wherein the communication system comprises aCharging Rule Function (CRF) which is in communication with a TrafficPlane Function (TPF) , wherein the CRF is configured to determine anevent trigger; provide the event trigger to the TPF; and receive acharging rule request from the TPF if the TPF monitors that the eventtrigger is met.
 18. The communication system according to claim 17,wherein the CRF is further configured to send a charging rule to the TPFin a charging rule provision procedure.
 19. The communication systemaccording to claim 17, wherein the event trigger includes a bearermodification event.